The preservation of food by dehydration has long been recognized. The earliest efforts at dehydration involved placing the food product, in an open container, for exposure to the sun and ambient conditions.
In more recent years, food dehydrators, with motor driven fans or blowers to force heated air through a cabinet or housing, and multiple shelves to receive the product to be dehydrated, have been developed for home use. A few of the many dehydrators developed for home use are discussed below.
To illustrate, U.S. Pat. No. 3,943,842, Bills et al, discloses a cabinet dehydrator (10) for long term preservation of food under close control of time, temperature, and humidity. Blower (32) obtains intake air from the surrounding atmosphere and forces same into the interior of the cabinet. As shown by the directional arrows in FIG. 1, the air passes over heater coil (50), through port (66) into the interior of the cabinet, and then circulates laterally between horizontally disposed trays (70). Baffles (80) are manually set to control the amount of hot air displaced across a given tray, or shelf. A circuit, shown in FIG. 8, regulates the rate at which moisture is withdrawn from the food being dehydrated. The circuit shown in FIG. 9 regulates the air temperature within the cabinet of the dehydrator.
U.S. Pat. No. 6,085,442, Erickson, discloses a modular food dehydrator (20), utilizing a heater blower assembly (34) located on a top surface of a dehydrator module as shown in FIG. 1. The heater blower assembly includes a motor driven fan (140, 142—see FIG. 6), a heating element (resistance wire 144), and an air distribution portion (housing 106 with distribution ports 114, 118, 120, 122) for directing heated air across the support surfaces. The heater blower assembly is reliably attachable to the dehydrator module. Space supports (72) maintain a gap between adjacent, horizontally disposed food trays (24, 25, 28) and serve as outlet vents to facilitate circulation of the heated air.
Similar food dehydrators, with horizontally stackable trays or shelves, are disclosed in U.S. Pat. No. 5,423,249, granted Jun. 13, 1995, to Michael F. Meyer, in U.S. Pat. No. 5,437,108, granted Aug. 1, 1995, to Steven Alseth, and in U.S. Pat. No. 5,878,508, granted to John L. Knoll et al. All three patents are assigned to American Harvest Inc., of Chaska, Minn.
The several dehydrators discussed above rely upon one or more trays, or shelves, retaining the food to be dried, within the interior of a cabinet or housing, in fixed position in parallel horizontal planes. Heated air is blow over the food, on the trays, to dry same; baffles, fans, porting, etc. control the circulation of heated air over the food retained on the trays, with varying degrees of effectiveness.
A different approach to preparing meat jerky, and other dehydrated foods, is disclosed in U.S. Pat. No. 5,974,957, granted Nov. 2, 1999, to David A. Ysen. The rotating food dehydrator includes a base (12) with an interior space, (as shown in FIG. 1). A food supporting mechanism, including trays (40), is supported by rotisserie assembly (32) with two sets of radially extending arms (36), (as shown in FIGS. 3 and 4). A heating mechanism, such as heating assembly (30), is adapted for generating heat within the interior of the dehydrator. Fans (25, 26, 28) circulate air about the food on the trays. The food supporting mechanism moves with respect to the air circulation mechanism, or system, during use of the dehydrator.
The electrically powered dehydrators discussed above represented a significant advance in efficiency over rudimentary dehydrators relying upon drying action, or curing, by exposure to the sun. However, the electrically powered dehydrators possessed certain disadvantages and operating deficiencies. For example, known dehydrators are bulky and consume significant space, both on a counter top, when in use, or in a storage area, when not in use.
Known dehydrators employ several horizontally disposed racks to receive the meat jerky, and difficulty is encountered in circulating air through the racks to evenly dry the contents of the racks. Blowers, vents, and louvers, are required in an effort to provide a degree of uniformity to the heated air to be circulated, and known dehydrators are thus relatively costly to purchase, operate and maintain. Also, the fat content in the jerky retained on the upper racks drips down onto the lower racks, thus diminishing the quality, and taste, of the product on the lower racks.
In order to overcome the shortcomings of known dehydrators in the areas of cost, complexity, uniformity of product, counter storage space, etc., the inventors have devised a simplified, vertically oriented dehydrator, utilizing a spring loaded basket, a racking grid, and a tray to receive the raking grid with several baskets secured thereto in a vertical orientation. The baskets are formed of first and second grates retained together by metal hinge clips. Receptacles on the grates are secured to upstanding pins on the racking grid to achieve vertical orientation.
The racking grid, after loading with the baskets locked thereon, is placed into an upwardly opening tray. The tray and its contents are inserted into a conventional oven for drying the jerky, or similar food product, in a simple, and efficient manner, at low temperatures, for a relatively short period of time.